LAUSR

Abstract There is emerging evidence implicating oxytocin receptor gene (OXTR) DNA methylation (DNAm) in social behaviour. This review investigated its association with autism spectrum disorder (ASD) characteristics and related social dimensions, both in individuals with and without ASD. Twelve articles investigating OXTR DNAm in relation to ASD, social perception/cognition and social anxiety were included. We found that hypermethylation is associated with (i) higher quantitative autism traits in adults, reflecting a higher incidence of autism characteristics, (ii) increased brain activity while performing social tasks (indicating a higher need for resources) and (iii) decreased functional connectivity. (iv) Contradictory, hypomethylation was found to be present in children (especially boys) with ASD and was also associated with more social anxiety. While the included studies displayed a large variability, for example in terms of population characteristics, analysed OXTR DNAm regions, and adopted scales/questionnaires, an initial developmental pattern of results emerged, suggesting an association between hypermethylation of OXTR and autism traits in adults. Nonetheless, future studies are warranted to corroborate these initial conclusions.